Percutaneous Scaphoid Pinning Using Ultrasound Guidance

摘要

A new procedure for percutaneous screw insertion in the scaphoid is proposed. The procedure involves pre-surgery planning using computed tomography imaging and intra-operative guidance using three-dimensional ultrasound. Pre-operatively, the desired screw location and orientation is chosen on a three-dimensional surface model generated from computed tomography images. During the surgery, ultrasound images are captured from the targeted anatomy of the patient using an ultrasound probe that is tracked with a Certus optical camera. The tracked probe enables the registration of the surface model and the surgical plan to the patient in the operating room. The surgical drill, used by the surgeon for screw insertion, is also tracked with the optical camera. A graphical user interface has been developed to display the surface model, the surgical plan and the drill in real-time. By means of this interface, the surgeon is guided during the screw insertion procedure. Our experiments on scaphoid phantoms demonstrate that the accuracy of the proposed procedure is potentially of the same order as an open reduction and screw fixation surgery. The advantages of this new procedure are a reduced risk of infections and minimal soft tissue damage due to its percutaneous nature. The procedure also reduces the exposure to ionizing radiation for patients and operating room staff due to the employment of ultrasound imaging instead of fiuoroscopy.